Electronic control system for automatic machines and the like



RN m C 6 I T A M O T U LA R 0 EF 5% ST S EY NS RL m m EC Sept. 14, 1954 ELECTRONIC MACHINES AND THE LIKE Original Filed July 1, 1946 INVENTORS WAYNE E. HARNESS JOHN 0. HRusY JR.

Sept. 14, 1 4 w. E. HARNESS ETAL 2,633,847

ELECTRONIC CONTROL SYSTEM FOR AUTOMATIC MACHINES AND THE LIKE Original Filed July 1, 1946 6 Sheets-Sheet 2 INVENTORS WAYNE E. HARNESS JOHN O. HRUBY JR.

Sept. 14, 1954 w. E. HARNESS ETAL ELECTRONIC CONTROL SYSTEM FOR AUTOMATIC MACHINES AND THE LIKE 6 Sheets-Sheet 3 Original Filed July 1, 1946 INVENTORS p 14, 1954 w E. HARNESS ET'AL 2,638,847

ELECTRONICi CONTROL SYSTEM FOR AUTOMATIC MACHINES AND THE LIKE Original Filed July 1, 1946 6 Sheets-Sheet 4 I65 66 67 as L 234 I66 o 5. 0 .l 65 so 52 a so ZNVENTORS I WAYNE E. HARNESS BY Jorm O. HRUBY JR.

Sept. 14, 1954 w ss ETAL 2,688,847

ELECTRONIC CONTROL SYSTEM FOR AUTOMATIC MACHINES AND THE LIKE 6 Sheets-Sheet 5 .www

Original Filed July 1, 1946 INVENTORS WAYNE E. HARNESS y Joan 0. HRUBY JR.

Sept. 14, 1954 w HARNESS 2,688,847

ELECTRONIC CONTROL SYSTEM FOR AUTOMATICv MACHINES AND THE LIKE OIfiginal Filed July 1, 1946 '6 Sheets-Sheet 6 fig- - INVENTORS WAYNE E. HARNESS BY Joan O. HRUBY JR.

Ag nt Patented Sept. 14, 1954 ELECTRONIC CONTROL SYSTEM FOR AUTO- MATIC MACHINES AND THE LIKE Wayne E. Harness, North Hollywood, and John 0. Hruby, Jr., Burbank, Ca1if., assignors to Lockheed Aircraft Corporation, Burbank, Calif.

Original application July 1, 1946, Serial No.

680,800, now Patent No. 2,620,876, dated December 9, 1952. Divided and this application January 23, 1952, Serial No. 267,878

7 Claims. 1

This invention relates to control apparatus and relates more particularly to electronic control systems for sequencing and timing pluralities of operations.

This application is a division of our copending application Serial No. 680,800, filed July 1, 1946, entitled Automatic Riveting Machine, now Patent No. 2,620,876, issued December 9, 1952.

There are many installations and machines where it is desirable or necessary to initiate and terminate the operations of several instrumentalities or mechanisms in sequency with or without time delays between the termination of one operation and the initiation of the next. For example, in our copending application referred to above, there is described a riveting machine embodying dimpling dies, punching means, rivet heading means, and other mechanisms that are operated in timed sequency to perform a, complete riveting cycle or operation. Furthermore, in such machines and in machines of other types, it is often desirable to perform sub-sequences of operation. Thus, in a riveting machine the work parts may be dimpled and punched to merely receive the rivets or, instead, the rivets may be successively inserted in previously formed holes and then successively driven or headed up.

It is an object of the present invention to provide a fully automatic control for machines of various natures, and other mechanisms, having a plurality of units or devices that require timed sequential operation which control is electronic in nature and therefore extremely accurate and which is capable of effecting either an entire sequence of operations or of effecting one or more sub-sequences of operations. The control system embodies a conveniently located selector switch that may be manually operated or set to bring about either the complete sequence or the subsequence operations.

Another object of the invention is to provide a control system of this character that may be readily set or conditioned to adjust or control the extent of movement, or the like, of the various instrumentalities of the machine. For example, in a riveting machine the depth of the dimples made by the dimpling dies and the height of the driven rivets may be varied or changed at will by manually adjusting conveniently located knobs, or the like.

Another and important object of the invention is to provide a control system of this kind that is itself sequentially operated or energized by moving parts of the machine or mechanism being controlled; for example by pistons, levers, rams,

or the like. The system includes manually regulable or adjustable switch means or contacts ope'rated or engaged by the movable machine parts to terminate certain operations and to initiate subsequent operations, the manual adjustments serving to vary or change the stroke or length of movement of the parts.

Other objectives and feature of the invention will be readily understood from the fOllOWiIlg detailed description of a typical preferred form of the invention wherein reference will be made to the accompanying drawings in which:

Figure 1 is a side elevation of a riveting machine incorporating features of the control system of the invention with certain parts broken away to show internal portions in vertical cross section;

Figure 2 is a fragmentary elevation of the other side of the machine with a portion broken away to illustrate certain valves and associated parts;

Figure 3 is an enlarged vertical sectional view of the punch actuating means;

Figure 4 is an enlarged fragmentary vertical section of the lower anvil assembly and associated parts showing a workpiece being dimpled;

Figure 5 is a fragmentary elevation view of the riveting feeding mechanism with a portion appearing in horizontal cross section;

Figure 6 is an enlarged vertical sectional view of the main cylinder taken substantially as indicated by line 6-B on Figure 1;

Figure 7 is a horizontal sectional View taken substantially as indicated by line 1-1 on Figure 8;

Figure 8 is a vertical sectional view with certain parts appearing in elevation taken substantially as indicated by line 8-8 on Figure 7;

Figure 9 is an enlarged sectional view of the diaphragm valve;

Figure 10 is a wiring diagram of the electronic circuit means; and

Figure 11 is a combined wiring diagram and flow diagram of the principal circuits and fluid pressure actuated means.

The control system of the invention is, of course, useful with machines, apparatus and installations of various natures where it is desired to initiate and terminate the operations of plural units or instrumentalities in timed sequence. Accordingly, the invention i not to be considered as necessarily limited or restricted to association with the riveting machines of the class herein described, this application of the invention being typical and by way of illustration. In

order to better describe the control system and its operation the riveting machine illustrated in the drawings will be described in a general way.

The machine includes a body l having a lower jaw I2 and an upper jaw |3 between which the work parts may be inserted. An upwardly projecting tubular boss I4 is provided on the lower jaw l2 adjacent its forward end and the active work engaging elements of the machine are arranged on the forward portions of the jaws l2 and I3. These elements include a die and anvil carrier |5 guided for vertical movement in the boss M. The carrier |5 receives the shank of a die l1 and the upper end of the die is made concave and shaped to aid in forming the dimples in the workpiece and in setting up the rivets. An elongate punch is slidably received in the tubular die H. A tubular stripper 2| is slidable on the exterior of the die l1 and its upper face is adapted to engage the under side of the workpiece W. The carrier l5, the punch 20 and the stripper 2| are each individually operated by suitable power mechanisms, for example pneumatic cylinder and piston means. The means for operating the carrier l5 vertically comprises a cylinder 23, a piston 24 operable in the cylinder and toggle linkage 26 operated by the piston rod 25. This assembly is illustrated in Figure 1. Actuating air pressure lines 21 extend from the opposite ends of the cylinder 23 to a four-way solenoid valve 288 in the jaw l2.

The means for operating the punch 20 includes a cylinde 28 attached to the carrier l5 and a piston 29 operating in the cylinder and having a rod 30 extending from the lower end of the cylinder, as shown in Figure 3. A lever 32 is pivoted at the lower end of the cylinder 28 and has one end engaged by the piston rod 38 and its other end acting upwardly against a rod 33 guided in the carrier |5. Intermediate push rods 35 and 36, illustrated in Figure 4, are arranged between the rod 33 and the punch 28 to slide in the carrier and die H. A spring 31 is engaged under compression between the rod 35 and an enlargement of the rod 36 to yieldingly support the punch 20 for retraction. The weight of the workpiece W is sufficient to compress the spring 31 and press the punch 20 downwardly and when the piston 29 is actuated downwardly the rods 33 and 35 move upwardly to compress the spring 31 until the upper end of the rod 35 engages the end of the rod 36 so that force is positively transmitted to the punch 20 to form an opening in the workpiece. Flexible lines 40 and 40 deliver actuating air under pressure to the opposite ends of the cylinder 28 and extend to a solenoid operated valve 209 in the jaw |2.

The stripper 2| is yieldingly urged upwardly to press against the underside of the workpiece W around the die l1. Vertical cylinder bores 4| are provided in the carrier l1 and rams 42 extend downwardly into the bores, as shown in Figure 4. The upper ends of the rams 42 are attached to the stripper 2| at 43. An air pressure line 44 supplies actuating air pressure to the bores 4| and extends from a main supply line 45.

The upper jaw |3 of the machine carries a dimpling shoe 41 and a riveting shoe 48, shown in Figures 6, '1 and 8. The shoe 41 has an upwardly sloping arm 49 and its offset lower portion removably carries a male dimpling die 50. The riveting shoe 48 has a similar arm 5| and its lower portion has a vertical opening 52. The shoes 41 and 48 are mounted for individual vertical movement and simultaneous horizontal shifting. Shafts 54 are slidable in spaced vertical openings 53 in the forward portion of the jaw l3. The arm 49 of the dimpling shoe 41 is fixed to one shaft 54 and the arm 5| of the riveting shoe 48 is secured on the other shaft. Spring means urge the shafts 54 to their upper positions where the shoes 41 and 48 are spaced clear of the work W. Bolts 56 extend through the tubular shafts 54 and are provided with nuts 51 for engaging the top surface of the jaw l3. Compression springs 58 surround the bolts 56 and are under compression between the lower heads of the bolts and internal shoulders 59 formed in the shafts.

The mechanism for shifting the shoes 41 and 48 includes lever arms 60 having sliding connections 6| with the shafts 54 so as to permit independent vertical movement of the shafts while remaining in rotation transmitting relation to them. The levers extend in parallel relation and their ends are pivotally connected with a link 62. The lever arms 68 and the links 62 are housed in the jaw l3 and piston mechanisms are supported on the jaw for shifting the link horizontally to move the shoes 41 and 48 between inactive positions and positions where they are in vertical alignment with the main ram 68. Horizontal cylinders 63 and 64 are secured to the opposite sides of the jaw |3 and have pistons 55 provided with rods 66 which extend into the jaw. The link [i2 has a lug 61 extending between the opposing inner ends of the piston rods 86. Air pressure lines 688 and 698 supply air under pressure to the outer ends of the respective cylinders 63 and 64. The parts are related so that upon introducing air pressure to the cylinder 63 the riveting shoe 48 is brought to the active position in line with the main ram 68 and upon supplying air pressure to the cylinder 84 the dimpling shoe 41 is moved to the position in alignment with the main ram. The shifting of one shoe to the active position simultaneously moves the other shoe to the inactive position.

The means for actuating the main ram 68 includes a vertical cylinder 69 mounted on the jaw l3 where its longitudinal axis is coaxial with the die I1. A piston 10 operates in the cylinder '63 and has a rod 1| extending downwardly from the jaw |3. The lower end of the piston rod 1| carries a chuck 12 for the ram 68. The ram 68 is engageable with the male dimpling die to drive the same downwardly against the work W when the shoe 41 is in the active position and is adapted to move downwardly through the riveting shoe 48 when the latter is in its active position to drive the rivet. The shank of the rivet is upset against the top of the punch 20 and the female die |1 so that vertical movement of the punch 28 controls the dimensions of the driven rivet. A stop screw 13, shown in Figure 3, is provided in the top of the cylinder 28 and is engageable by the piston 29 to limit downward travel of the punch 20. Adjustment of the screw 13 controls the position of the punch 20 for the riveting operation.

Referring again to the main cylinder 69, shown in Figure 6, a reduced stem 15 extends upwardly from the piston 16 and slides through an opening in the upper head of the cylinder. A washer 16 is secured on the upper end of the stem 15 and a spring 11 is arranged under compression between the cylinder head and this washer to returnthe piston 1|) and punch 63 to the raised position when air pressure is released from the cylinder. A cap 18 on the cylinder 69 houses the projecting stem I5, spring 11 and disc I6.

The mechanism for feeding rivets to the riveting shoe 48, shown in Figures 2 and 5, includes a hopper on the outer end of the jaw I3 for containing a supply of rivets and the hopper discharges into a track 83. A shiftable rivet selecting gate 85 is slidably arranged between the lower end of the track 83 and the upper end of a rivet discharging element 80. The element 80 has a passage 81 for guiding the rivets to the riveting shoe when the latter is in the retracted position. The passage 81 is offset horizontally from the track 83 and the gate 85 shifts the rivets one at a time from the track to the entrance of the passage. The gate 85 has a T shaped notch 88 for receiving an individual rivet and this notch is adapted to register with the track 83 to receive the rivet therefrom. Upon shifting of the gate the notch 88 comes into alignment with the passage 81 to discharge the rivet.

Cylinder and piston means is provided to shift the gate 85 to the rivet discharging position. A cylinder 90 is attached to the track assembly and the gate 85 has a piston 0| operating in the cylinder. A pressure line 92 communicates with the outer end of the cylinder and extends to a solenoid operated three-way valve 93. An air line 920 continues from the valve 93 to a valve I14, to be later described. A spring 95 is engaged under compression between a bracket 04 and the end of the gate 85 to restore the gate to the position shown in Figure when the valve I14 is operated to discharge pressure from the cylinder 90.

Prior to each riveting operation a rivet is supplied to the shoe 48 by the track and gate means just described. This rivet is retained in the shoe 48 While the latter is shifted into alignment with the main ram 68 and until it is forced into the opening in the workpiece W. The workpiece W is securely clamped between the dies I! and 50 during the punching operation and the punch 20 is operated upwardly to form the opening in the dimpled material. Figure 4 shows the parts in the position for the punching operation where it will be seen that the die 50 has an opening I00 for receiving the punch 20 as it moves upwardly. The punch 20 displaces slugs of material upwardly through the opening I00. A lateral opening IOI joins the upper end of the opening I00 and an air pressure nozzle I02 is threaded in the opening to discharge a stream of air across the top of the opening I00. An air pressure line I03 leads from a four-way diphragm valve I04 to the nozzle I02, the air supplied to the opening IOI serving to discharge or eject the slugs of material.

The elements thus far described are fluid pressure operated in the embodiment illustrated being pneumaticall actuated, and the invention provides a versatile, dependable electronic control system for obtaining automatic, sequential and independent actuation of the several mechanisms to perform the dimpling, punching and riveting functions. Figures and 11, and more particularly in Figure 10, we have illustrated what may be termed the internal electronic circuit which comprises an initiating stage A, a plurality of intermediate stages B, C, D, E, F and G, and a reset stage H. The initiating stage A includes a thyratron or gas filled triode tube I05 having a current limiting resistor I06 connected in its grid circuit and a surge protection condenser I01 tapped into the grid lead. A relay or switch means is provided to initiate firing of the tube I05. As shown in Figure 11, this means comprises a relay I08 which I nects terminals A and A 6 has normally open and normally closed contactors, and a condenser I09 is connected with the normally closed pole of the relay. A lead 9 extends from the normally open pole or contact of relay I08 to terminal A The grid of tube I05 is connected with the lead 9. A D. C. power source I I I is provided to give bias for the control of the grids of the tubes in the various electronic stages. A common line I I0 extends from the negative side of the bias source III to a limiting resistor 8 of high enough resistance to allow condenser I09 to temporarily bring the bias on tube I05 to a value low enough to render tube I05 conductive. Resistor 8 is connected between lines 9 and I I0. Condenser I09 has a large value as compared with the value of condenser I01 and resistor 8 has a high value as compared with the value of resistor I06. Thus in a typical installation condenser I09 may have a value of 0.1 microfarad while condenser I01 has a value of 0.01 microfarad and resistor 8 may have a value of /2 megohm while resistor I06 has a value of 2500 ohms. Prior to closing of the pedal operated switch I54 the condenser I00 is discharged through the normall closed contactor of relay I08. Manual operation or closing of the pedal switch I54 energizes relay I 08 and the relay connects the discharge condenser I00 with terminal A and lead 9 to reduce the potential on the grid of tube I05 to zero. This makes the tube I05 conductive.

The initiating stage A further includes a relay I I3 having three posts or terminals A A and A for connecting with external circuits, which will be later described. One side of the relay winding is tied into the plate of the tube I05 by line H9 and a lead I20 connects the other side of the Winding with a suitable power supply I22 through a network I23-I24, to be later described. One blade or contactor I Id of the relay is initially in a position where it electrically connects terminals A and A and upon energization of the relay, this connection is opened and the contactor con- The second movable blade or contactor I I5 of the relay initially makes electrical connection between a terminal H0 tied into the bias source III through lead III] and a lead II'I. Upon energization of relay II3, contactor II5 breaks this connection and moves to a position where it connects the lead I H with the terminal of a potentiometer I I8. The other terminal of the potentiometer is connected with a grounded timing switch I2I. Avoltage limiting resistor I23 is interposed in the power line I20 and a peak charge condenser I20 is tapped off the line I20 to ground at a point between the resistor and the relay H3. The function of the above described elements will later become apparent.

The initiating stage A is associated with the first intermediate stage B to control actuation thereof. Referring again to Figure 10, intermediate stage B comprises a thyratron tube I25 having a lead I20 extending from its grid and provided with a current limiting resistor I2I. The lead I26 extends to a terminal B which has connection with an external circuit, to be later described. The relay I28 of the first intermediate stage B has one terminal of its actuating winding connected with the plate of tube I25 and a lead I29 connects the other terminal of the winding with the power line I20. A voltage limiting resistor I3I is interposed in the line I29 and a peak charge condenser I32 is connected to the line at a point between the relay coil and the resistor. The relay of stage B is similar to the relay of the initiating stage A and includes a blade or contactor I33 initially in a position where it connects terminals B and B Upon energization of relay I28, the contactor I33 breaks this connection and electrically connects terminals B and B The second blade I36 of the relay initially makes connection between a terminal I34 in the bias line H and a line I35 extending to the timing resistor and condenser circuit of the next intermediate stage C. Upon energization of relay I 28, the blade I36 breaks this connection and completes a circuit between said line I35 and a terminal of a timing potentiometer I31. A switch I38 is connected between the other terminal of potentiometer I31 and ground. The above described lead II'I extending from blade II5 of relay II3 connects with the grid lead of tube I25 and with a timing condenser I40. A maximum timing resistor MI is associated with condenser I40. Condenser I40 and resistor |4I are operable to timeout the tube I25 as will be described below.

Now referring again to initiating stage A, it will be assumed that initiating relay I08 is operated to fire tube I05 as described above. In the event switch I2I is closed at this time, firing of tube I05 energizes relay I I3 to complete a circuit through terminals A and A and to complete a circuit from condenser I40 through potentiometer I I8 to ground. Completion of the circuit through the potentiometer discharges the charge in condenser I40 to the extent that tube I25 of the intermediate stage B becomes conductive to energize relay I28 of stage B. This timing-out of tube I25 is controlled primarily by potentiometer II8, resistor I4I being of an extremely high value with respect to the potentiometer. Thus it will be seen that if switch I2I is closed when relay II3 is energized, timing-out of the tube I25 is determined by the setting of potentiometer I I8. In the event switch I2I is open when tube I05 of initiating stage A becomes conductive, energiza-' tion of relay I I3 brings the maximum timing circuit comprising condenser I40 and resistor I4I into play. Because of the high value of resistor I4I, the tube I25 of stage B is held nonconductive for a substantial period for the purpose to be later described.

Intermediate stages C, D, E, F and G may be identical with intermediate stage B just described, and are related one to the other in the manner in which stage A is related to stage B. Accordingly, in order to simplify the disclosure, the details of stages C, D, E, F and G are omitted from the drawings, and in referring to the elements of these stages, reference numerals will be used corresponding to the reference numerals applied to corresponding elements of stage B with the respective exponents C, D, E, F and G added thereto. However, in the case of the external terminals of stages C, D, E, F and G, these are designated C C C and C D D D and D and so on, as clearly appears in Figure 11.

When lead I20 is energized before the machine is operated, condensers I24, I32 and I32 to I32 inclusive are charged to the maximum peak voltage of power supply I22. When tube I05 becomes conductive, the peak charge of condenser I24 is available for quick energization of relay II3. Upon energization of relay I I3, the charge is partially drained off from the condenser and resistor I23 becomes part of a dividing network lowering the continuous voltage applied to relay I I3. This allows the relay to remain energized without overheating. The peak voltage networks I3I, I3I to I3I and I32, I32 to I32 of the several intermediate stages B to G inclusive, function in a similar manner when their respective tubes I25 and I25 to I25 inclusive become conductive.

The several stages A to G inclusive are interconnected in the following manner, as shown in Figure 11. A conductor or lead 2 [3 extends from a power supply line I92 to terminal G of stage G. Relay I28 normally connects terminal Ci with terminal G An interconnecting line 2I4 connects terminal G2 with terminal F of stage F. Relay I28 normally connects terminals F and F and an interconnecting line 2I5 joins terminals l? and E Relay I28 normally connects terminals E and E and an interconnecting line 2I6 joins terminals E and D Relay I28 normally connects terminals D and D and a line 2I'I joins terminals D and C Relay I28 normally connects C and C and a line 2l8 joins terminals C and B Relay I28 initially connects terminals B and B and a connecting line 2I9 joins terminals B and A Terminal A is connected with terminal A by the contactor II4 of relay II3 when the same is in its de-energized condition. It will be seen that this arrangement interlocks the several stages in such a manner that delivery of current to their respective terminals 2 and 4 depends upon the position of their relays.

The internal electronic circuit further includes a reset stage H for breaking the full wave D. C. voltage from the power source I22 to the tubes I05, I25, I25 I25 I25 I25 and I25*, and for discharging the several condensers I24, I32 I32 I32 I32 and I32 to render the related tubes of stages A to G inclusive, nonconductive, thereby restoring these stages to their normal or initial condition. Reset stage H includes a gas-filled triode or thyratron tube I42 having a current resistor I2'I in the portion of its grid circuit extending to its terminal H The lead I35 from the relay blade I30 of stage G taps into the grid lead, and extends to a timing condenser I. A maximum timing resistor I4I is associated with the grounded condenser I40. It will be seen from an inspection of Figure 10 that tube I42 of reset stage H becomes conductive in the same manner as the tubes I25 of the intermediate stages, either through the timing-out action of potentiometer I3I or resistor MI. The reset stage H further includes a relay I43 connected between the plate lead I44 of tube I42 and a lead I45 extending from the half-wave portion of power source I22. A current-limiting resistor I46 is interposed in lead I45 and a smoothing condenser I4'I is connected in the lead across the winding of relay I43. The relay has a contactor or blade I48 connected with a terminal of above described line I20 and operable between a position where it engages a grounded pole I49 and a pole connected with a line I50 carrying full wave voltage from the power supply I22. When the relay I43 is in the de-energized condition, the blade I48 is in engagement with the terminal of line I50.

When the tube I42 is made conductive, as described above, the relay I43 breaks the full wave D. C. voltage circuit to the tubes I05, I25 and I25 to I25 inclusive. Energizing of relay I43 also brings the blade I48 into engagement with the grounded post I49 to discharge condensers I24, I32 and I32 to I32 inclusive, rendering the tubes of several stages A to G inclusive, nonconductive and allowing their related relays II3, I28 and I28 to I28 inclusive, to restore to their initial positions. Restoration of relay I28 applies full negative voltage from source III to tube I42 of stage H, making the tube nonconductive. This restores relay I43 and completes the full sequence cycle. It will be observed that the internal electronic circuit is automatic upon closing of the switch I54 to carry out a full sequence of operations throughout the several stages A to H inclusive. A case I56 mounted on a side of the'body I contains the above described electronic stages A to H inclusive, and the power supply means I22.

The external circuits of the system include a master switch I52 for controlling delivery of current to the power supply I22. An indicator lamp I53 may be connected with the power sup ply to indicate the position of the master switch. The above described initiating relay I08 is connected in series with a pedal operated switch I54 so constructed that depression of a pedal closes the switch. A safety switch I55 is also connected in series with the foot switch I54 and relay I08, and is operated to allow heating of the tubes of stages A to H inclusive. The above described solenoid valve 208 for controlling delivery of air under pressure to cylinder 23 has one lead 2I0 extending to the power supply and has another lead I 58 extending to a switch I59 connected with a second power lead I60. The switch I59 is a double pole switch and is also connected in series with the foot switch I54, safety switch I55 and relay I08. Thus in order to condition the machine for operation, the switch I59 must be closed to actuate the piston 24, which brings the anvil or carrier I5 to its raised operative position. .With-the-switches. I55 and I50 ..closed; the foot switch l54.,is closed to initiate operationof the machine. .Closing of the switch I54 .energizes relay. I08, .which applies D. .C.- current 'toall stagesA to l-I inclusive, of the internal electronic circuit and-:aLpplies a zerowcharge of gthemcom densen -'I03.,to the grid of the .tube: I05 of, initiating stage A. Asabove described, this fires tube I05 and actuates relay II 30f stage A. A lead I extends from post A of stage A to a relayITI whichy5has a poleand blade I12=interposed in a power; line-x113 extending to awsol'enoid operated four-way. valve I14. Upon-'Lfirings-of tube I05 of stage A, relay I H is energized and solenoid valve I14 is reversed or operated. Solenoid valve I14 is operable to connect an air pressure supply manifold I15 with the pipe 690 leading to the right-hand shifting cylinder 64 so that the piston therein is operated to shift the dimpling shoe 41 into alignment with the main ram 68. This actuation of solenoid Valve I14 also supplies air under pressure from manifold I15to lines 920 and 92 leading to the above described rivet gate or selector cylinder 90. It will be seen that energization of stage A results in shifting of the dimpling shoe 41 into alignment with the main ram and delivery of a rivet into passage 81 of the rivet feed means.

A selector switch I62 is provided to either condition the internal electronic circuit for the full sequence of operations of the machine or for punching only, or for riveting only as desired. The switch I62 is interposed between the posts or terminals B C and D of stages B, G and D, and certain external contacts embodied in the machine. A line I65 extends from post B to a post of the switch I62 and the related switch blade I64 is engageable therewith to complete a circuit through a line I65 extending to an external contact I66. As illustrated in Figure 7, contact I66 is in the nature of a post extending through .a tubular insulating screw-300 which,

10 in turn, is threaded through an opening in the head of the left hand shift cylinder 63. The inner end of the contact I66 is engageable by piston 65.

The next phase of the operation is effected by engagement of the left-hand shift piston 65 with the above described contact I66. Contact I66 is connected with terminal B of the first intermediate stage through the medium of line I65 and selector switch blade I64 so that engagement of the piston with the contact I66 grounds this circuit and thus renders the tube I25 conductive. The timing switch I 2| of stage B is open at this time, and the maximum timing circuit I40--I4I allows ample time forthe grounding of circuit I64 and I65 as just described. The conductive tube I25 energizes relay I28 and contactor I33 comes into engagement with terminal 3*. This energizes a relay I11 having a contactor I18 interposed in a lead I19 extending from a solenoid actuated four-way valve I to a common A. 0. power lead I91. Valve I80 controls communication between the air pressure manifold I15 and a line I8I, and communication between the line I8I and the atmosphere. Line I8I extends to one end of a diaphragm valve I04 illustrated in detail in Figure 5.

Diaphragm valve I04 includes a tubular body I82 provided at its ends with caps or heads I83. A partial partition in the body carries a tubular seat member I84 and defines two end chambers I85 and I86. The member I84 extends into these chambers and its end surfaces constitute. an nular seats which oppose the heads I83. Flexible diaphragms I81 and I88are secured against the ends :of the. body I82 to extend across the chambers ,1I85-ahd I86. 5' I The .diaphragms area-movable intoxand: "out aof engagement;:withathe adjacent ends; of the seat :member i I84: An exhaust port I89 communicates; with-v the innerwportion" of chamber. I86 and :an. air pressure supply line I 90, leading: from manifold I15, communicates *with the inneraaportion i of :chamberw'I85Kf It-wi11= be observedethat the effective. areas of the diaphragms181 and I88 exposedtospressureintro duced into the outerends of -thechambers I 85 and I86, are considerably larger than the areas of the diaphragms exposed at the interior of the seat member I84 and the areas exposed around the seat member.- Accordingly, pressure admitted to the outer end of a chamber holds the related diaphragm I81 or I88 engaged with the seat member I84 and resists comparable pressure within the seat member I 84 or within the annular space surrounding the seat member. Release of pressure from an outer end of a chamber I85 or I86 allows the related diaphragm to open from the seat member. A pipe I90 communicates with the interior of the seat member I84 and extends to the upper end of the main cylinder 69.

When relay H1 is energized to reverse the solenoid actuated valve I80, pressure is relieved from line I8I and the outer end of chamber I85. This allows diaphragm I81 to move to the open position so that air under pressure pipe I90 flows through pipe I96 to the upper end of the main cylinder 69. Substantially simultaneously with this action, air under pressure is supplied to the outer end of chamber I86 to close the diaphragm I66 against seat member I84 and thus close off the exhaust I89.

The means for effecting reversal of diaphragm l 88includes a relay l8I energized upon actuation of relay I11. A lead I92 extends from the coil a pipe I194 leading to the outer end of diaphragm valve chamber I86 to either connect the same with air pressure supply manifold H or the atmosphere. Energization of relay I9I reverses valve I93 so that air under pressure is supplied to pipe I94 and chamber I86. It will be seen that upon firing of tube I25, valves I60 and I93 are reversed to reverse the diaphragm valve I04 so that air under pressure is supplied to the upper end of the main cylinder 69 to actuate the ram 68 downwardly.

In accordance with the invention, means is provided for limiting the initial downward stroke of the main ram 68 so as to control the depth of the dimple formed in the work W, and the stroke-limiting means serves to initiate operation of the intermediate electronic stage C. A dimple depth contact is provided in the lower portion of the main cylinder 69 to be engaged by the piston 10 as it descends. A plate I98 of dielectric material is secured to the under side of cylinder 69 and carries a bushing I99. A tubular thumb screw 200 is threaded upwardly through the bushing and passes freely through an opening in the cylinder wall to enter the cylinder. elongate contact stem I is slidable in the thumb'screw 200 and has a head at its lower end for contacting the under side of the thumb screw knob. A spring 202 is engaged under compression between the screw 200 and a head on the upper end of the stern 20I to urge the stem upwardly. It will be seen that rotation of the screw 200 vertically positions or adjusts the contact stem 20I. The knob of the screw 200 is conveniently accessible at the front of the machine so that the operator may readily vary or regulate the depth of the dimples to be formed.

A lead or conductor 203 is electrically connected with the contact stem 20I through the medium of the bushing I99 and screw 200, and

extends to the post 0 of the intermediate electronic stage C. When the main piston 10 moves into engagement with the contact stem 20I, the grid circuit of stage C is grounded to make the tube I conductive. This, in turn, energizes relay I26 to bring the blade I33 into contact with post C. A line 205 extends from terminal C to a relay 206, a circuit for energizing relay 206 being completed through lead 205, contactor I93 and post C Relay 206 includes a post and contactor 201 interposed in a lead 206 extending from power line I91 to one side of the solenoid of a four-way valve 209. The other side of this solenoid is tapped into line 2 I0 extending to the power supply I22. Valve 209 governs the above mentioned pipes 40 and 40 which lead to the upper and lower ends respectively of the punch operating cylinder 28. When the solenoid of valve 209 is in the normal de-energized condition, the valve connects the pipe 40 with an air pressure supply line 2I2 so that the piston 29 is held in the upper position. Upon reversal of the valve 209, effected by operation of relay 206, pipe 40 is put into communication with pressure line 212 and pipe 40 is allowed to exhaust to atmoslead 205.

-- and the tube is made conductive.

phere. This actuates piston 29 downwardly and the punch 20 is forced upwardly to form an opening in the dimpled workpiece. It is to be observed that air pressure is maintained in the main cylinder 69 at this time and the work W is tightly clamped between the dies I1 and as it is punched. This assures the production of a true clean opening in the work with a minimum of distortion.

As described above, slugs S of the sheets or workpieces W are pushed upwardly through the opening of die 50 when the punch is operated. The invention provides for the delivery of air under pressure to the nozzle I02 to blow these slugs free. The above mentioned line or pipe I03 supplying the air nozzle I02 is in communication with the pipe I94 which extends between solenoid operated valve I93 and diaphragm valve I04. When the valve I93 is reversed to close oil the exhaust I89 of the diaphragm valve, as previously described, air under pressure is also supplied to the nozzle I02 through line I03. A stream of air discharges from the nozzle I02 at a substantial velocity so long as the solenoid of valve I93 remains energized. Accordingly, the slugs S formed during the punching operation are blown clear through the opening IOI by the air blast as the unch approaches the upper end of its stroke.

At the instant the blade or contactor I33 of stage C is operated toward post C the circuit to the coil of relay of I11 is opened to de-energize the relay Ill. The current to relay I1! is carried by relay I28, line 2I0, relay I28 and a line 500 extending from post B to the winding of the relay. When relay I28 is energized, as just described, this circuit is broken between terminals C and C De-energization of relay I'II causes reversal of solenoid operated valve I80, which, in turn, seals ofi both ends of the diaphragm valve I04 to lock the ram 68 in its down or dimpling position. When blade I33 moves into engagement with terminal 0* a circuit is completed to the winding of relay 206 through Energization of relay 206 energizes solenoid actuated valve 209 to supply air under pressure to cylinder 28 through line 40. This actuates the punch 20 to form an opening in the workpiece W.

The above described actuation of the punch 20 causes operation of electronic stage D, which in turn de-energizes relays I9I and 206. As shown in Figure 3, a rod 22I is attached to the cylinder 28 of the punch operating mechanism and a sleeve 222 is slidable on the rod. The sleeve is yieldingly urged upwardly by a spring 223. A projecting arm on the sleeve 222 carries an insulated contact 224 in position to be engaged by the lever 32 when the punch 20 reaches the upper end of its movement. A conductor 225 extends from contact 224 to the terminal D of stage D. Upon engagement of the lever 32 with contact 224, the grid circuit of tube I25 is grounded to discharge condenser I40 This energizes relay I20 to break the connection between terminals D and D. This in turn de-energizes the relays I9I and 206. De-energization of relays HI and 206 results in reversal of the solenoid operated valves I93 and 209 so that the spring 11 is free to restore the piston I0 to its raised position and to move the ram upwardly out of engagement with the die 50. Valve 209 is also reversed to cause the punch 20 to descend. Relay III remains energized at this time to hold 13 valve I14 in the actuated position so'thatthe dimpling die 50 remains in line with the ram 68. Relay III is locked in by a lead 226, tapped into theinterconnecting line 2I6 and extending to a second contactor 221 of the relay, the contactor being connected with a pole of the relay winding.

The invention provides means whereby restoration of the ram 68 reverses the positions of the dimpling shoe 4! and the riveting shoe 43. A tubular screw 229 is adjustably threaded through a bushing 230 secured in a di-electric plate on the hood I8 of the main cylinder 69. Av contact stem 23I is shiftable in the screw and extends downwardly into the hood. A spring 232 is engaged between the screw 229 and a head on the lower end of the stem 23I to urge the stem downwardly to its lowermost position. The stem 23I is engaged by the upper end of the rod I when the piston I0 returns to its upper position. A conductor or line 233 extends from a post on the bushing 230 to the terminal E of stage E. When the contact stem 23I is engaged by the rod I5, the control grid circuit of stage E is grounded so that tube I25 becomes conductive to energize relay I28 This breaks the connection between terminals E. and E3 and relay I1I is de-energized so that valve I14 is reversed. Reversal of fourway valve I14 exhausts air pressure from line 690 and cylinder 64, and supplies air under pressure to line 580 and cylinder 63. The resultant actuation of piston I65 shifts the dimpling shoe 4! to an idle position and moves the riveting button or shoe 48 carrying the previously introduced rivet into alignment with the main ram 68.; It will be. observed thatat this .timelall externalirelays are ,de-energized. The machine is new in, condition forvthe riveting foperation.

Shifting of the 'rivetingshoe 48 to the active position gisuimmediately followed by. downward actuation of the main ram 08. ..The means. for accomplishing this includes acontact 234 carried by an insulating screw 235 threaded through an opening'iinuthe end of theright-hand shiftcylinder 64 so as to be. .engageab1ebythepiston of that cylinder when it returnsto the outer position. A conductor or. line 236 is connected to contact T234 .and, extends to terminal Fl 'of stage F. Engagement of thel'returning'l pistoncwith contact 234 grounds .the'control' circuit of stage E to render the tube I25 conductive. so that relay I28 is venergized... In. accordance .with the 'inventiongthis re-energizes or reverses the four-way valvesIIlU and'IEl3.v The meansfor accomplish ing this operation includes a" relay 23 8 havinga blade 239jinterposed in a line 240 extending from the A. C. powerline I91 to onepoleflof thesole noid operated valve I80. I The relay has a second blade I in a line 242 extending from the A. C. I

power, -line; I9'I to ,theline I96 of the. solenoid operated valve,. l93. A. conductor 243 extends from the terminal'F of stage F'to the winding of relay 238 so that energization of relay Iii-8 v energizes relay .238.and operates valves I80 and I93. In accordance withrthe previousdesci'iptionofoperation, actuation of' the valves I80 and "I93supplies air under-pressure to the upper end of the main cylinder 69 through the medium of the diaphragm valve I04. This operates the ram 68 downwardly to drive or upset the rivet releasably held in the shoe 48. As shown in Figure 7, the rivet is passed through the punched opening in the work W and its shank is upset against the upper end of the punch 20 and the surface of die I1.

.1 The invention providesad'justable meansior accurately determining the depth of therivet and for initiating the next stage of operation. This means includes what we will term a rivet depth contact 244 positioned to be engageable by the main piston I0. A tubular thumb screw 245 is threaded through a bushing 246 in the insulating plate I98 and passes freely into the lower end of the cylinder 69, as best shown in Figure 6. The rivet depth contact 244 is in the nature of an elongate stem shiftable in the screw 245 and provided with heads at its upper and lower ends. A spring 241 is engaged between the upper head of the contact and the screw 245 to urge the contact to its upper position projecting a considerable distance beyond the screw. The contact 244 is at a lower elevation than the dimple depth contact stem 2M and is not engaged during the dimpling stroke of the ram 68. As the piston I0 moves downwardly during the riveting stroke, it engages and depresses the stem 20I, but at this time the circuits associated with the stem are idle. A lead 248 extends from a screw or post on a bushing 246 to the terminal G of electronic stage G. When the piston I0 engages the stem 244, the control grid circuit of tube I25 is grounded and the tube is made conductive. This energizes relay I28 so that its blade I3? moves out of engagement with terminal G As a result, the circuit to terminal F and line 243 is broken to de-energize relay 238. This de-energizes or reverses valve I and I93 so that the diaphragm valve I04 operates to cut off the air supply to the main cylinder 69 and toexhaust air therefrom. The spring I! restores the piston. I0 and,

v The reset stage 1-1 of electronic system is operated substantially simultaneously with. re:-

electronic system. The contactor of relayHB.

moves to the pole. I49 toapply full negative-bias, voltage, to the condensers, I24; I40 and I,40..to I 40 inclusive. through-the medium. of contactors I36 to I36 and H5, to preventtthe tubes of the several stages .from becoming conductive. when voltage is again applied to thesystem. Thus they electronic system is fully restored for the next-op eration. I f a 1 The machine may "be conditioned to perform given individual operations or a sequence ofsea lected operations short of a'full sequential cycle. For example, the machine may be set to'dimple the work W and punch an opening therein for the subsequent reception of a rivet. The above mentioned selector switch I62 is embodied in the external circuit to provide for the performance of selected operations or sequence of operations. The selector switch includes the previously mentioned blade I64, and additional blades 250,25I and 252. Figure 11 shows the selector switch in 15 position for a full sequence cycle of the machine. When desired to only dimple and punch the work W, the selector switch is moved to a position where its blades 250, 25I and 252 function as described below.

In considering the following description of operation where the machine is employed for dimpling and punching only or for rivet inserting and driving only, the relationship between the resistances in the control grid circuits of the several electronic stages is of importance. When the relay.l28 is of a given stage is open or in the initial position, the resistance in the circuit from the condenser I48 to the line I Ill is less than the resistance in the circuit from the condenser to the terminal B C D etc, as the case may be. Accordingly, the tube I25 is not made conductive, even though this terminal grounded by the operation of some external element of the machine. The relay I23 of a preceding electronic stage must be energized or closed to render the tube I25 conductive by the grounding of the control grid circuit through the related terminal 13 C D etc. The resistance I2! adjacent the terminal is of such a value that upon grounding of the circuit, the related tube I25 is made conductive almost immediately by bleeding off the charge in the associated condenser I40.

The dimpling and punching cycle is initiated in the same manner as the full sequential cycle by closing switches I54, I55 and I59. This results in operation of electronic stage A to shift dimple die 41 into position between die I I and ram 68. Stage B then operates automatically to supply air under pressure to the upper end of the main cylinder 69 to move the ram downwardly whereby a dimple is formed in the work W by the dies Ii and 5E. The dimple depth contact lllI is engaged by the piston to operate stage C at the completion of the dimpling operation. Actuation of stage C maintains air pressure in the main cylinder 69 and causes air under pressure to be supplied to cylinder 28 to actuate the punch 20. The punch forms an opening in the material held by the dies I! and 50. At'the completion of the punching operation, lever 32 engages contact 224 to energize or fire electronic stage D, which in turn effects the return of the ram 5? and punch 20 to their idle positions. Piston III comes into engagement with contact 23I as the ram approaches its uppermost position, and electronic stage E is operated. This causes the rivet shoe 48 to move into position between the ram 68 and die Il'. However, there is no rivet contained in the shoe 48 at this time, and the shoe is not brought into operation during the dimpling and punching sequence. Blade 252 of the selector switch I62 is connected between a lead 254 extending from power line Il-ll and a line 25-5 extending to one side of the solenoid operated three-way valve 93. When the selector switch is positioned for dimpling and punching only, the blade 252 closes the circuit just mentioned to operate the valve 93 to a position where the air pressure supply is cut off from the rivet gate cylinder 90. The rivet gate 85 is thus held in a position where rivets cannot feed into the shoe 48.

Electronic stage F is grounded by the selector switch to fire immediately upon the operation of the electronic stage E, and before the right-hand shifting piston engages contact 234. Electronic stage G is also fired immediately. Contact 251 of the selector switch is at this time positioned to ground a tap 256 from the line 248 extending.

to terminal G Electronic stage G clears all the external relays of the system and serves to time-out tube I42 of stage H through circuit I3I I35 and I40. This clears out the electronic circuits for the succeeding operation.

When the machine is to be used to insert rivets in previously dimpled and punched openings in the workpiece and then to drive the rivets, the selector switch I62 is moved to the rivet only position where the blades I45, 250 and 25I control the related circuits. In carrying out the rivet only operation, electronic stage A is operated by closing switch I54 and the other switches in the initiating circuit. This fires or operates stage A as above described. With selector switch I62 in the rivet only position, the blade I64 engages a terminal to place a resistor 260 in the circuit I65 which connects terminal B and contact IE6 at the left-hand shift cylinder 63. The resistor 260 is of such a value that it delays firing of tube I25 of stage B for a sufficient time to allow the rivet to drop into the shoe 48 from the passage 81. The automatic rivet only cycle is substantially reduced in time by reason of the fact that stages C and D are immediately grounded out, as will be described below. This shortening of the cycle of operation is compensated for by the delay in the firing of stage B effected by resistor 260, and the rivet is given ample time to fall into the rivet shoe before the shoe is shifted. Engagement of shift piston 65 with contact I66 results in firing of stage B as described above. This conditions stage C for operation, and blade 25!] of the selector switch I62 grounds line 203 so that stage C fires immediately. This conditions stage D, which also fires immediately because blade 25I of the selector switch grounds line 225 leading to the terminal D Thus stages C and D are operated in rapid succession and do not depend upon external circuit conditions established by machine operation for their actuation. Stage E of the electronic system operates as above described to cause the rivet shoe 48 carrying the rivet to be shifted into position in line with the main ram 68. Stage F then operates as previously described to actuate the main ram, and the rivet is driven. Electronic stage G operates at the completion of the rivet driving operation by reason of the engagement of piston III with the rivet depth contact 244 and actuation of stage G causes the main piston and ram 68 to return to their upper positions. Re-set stage H operates as in the previously described cycles, and the system is restored to the normal condition for the next rivet only sequence. The machine may be repeatedly operated to insert and drive rivets in previously dimpled and punched openings by merely actuating the foot switch I54.

Switches I2I, I38 and I38 to I38 inclusive may be omitted if desired. However, they are illustrated in the preferred embodiment of the invention to indicate that the successive stages of the electronic system may be timed out to perform or permit the performance of special or selected machine operations as conditions may require.

From the above detailed description it will be seen that we have provided a fully automatic riveting machine that may be employed to carry out a complete sequence of operations, including the dimpling and punching of the work parts, the insertion of the rivets and the driving of the rivets. The machine may also be set to simply dimple and punch the work parts or to insert 'rivets in previously dimpled and punched openings and then drive the inserted rivets. Thumb screw 200 may be easily adjusted to regulate the depth of the dimples to be formed in the workpieces, and thumb screw 245 may be manipulated to regulate the depth of the rivets. The thumb screws 200 and 245 are located where they are conveniently accessible to the operator, and adjustment of the machine may be accomplished without any delay whatsoever. It is to be observed that the several primary or active elements of the machine are directly operated by cylinder and piston mechanisms, and there are no intervening linkages subject to wear and malfunctioning. The electronic control system assures properly timed sequential operation of the several machine parts and is such that simple setting of the selector switch I62 conditions the machine either for the performance of the full cycle of operations or for dimpling and punching only, or riveting only. The invention provides a trouble-free fully automatic machine capable of rapidly carrying out its several functions.

Having described only a typical form of the invention, we do not wish to be limited to the specific details herein set forth, but wish to reserve to ourselves any variations or modifications that may appear to those skilled in the art and/or fall within the scope of the following claims.

We claim:

1. An electronic control for a machine having a plurality of moving parts comprising an initiating stage including a tube having a plate circuit and a grid circuit, a relay connected in the plate circuit to be energized when the tube be comes conductive, a negative bias potential source, a connection between said. source and the grid circuit to provide a bias to hold the tube non-conductive, manually operable means controlling said connection to reduce said bias on the grid circuit and thus render the tube conductive, actuating means for moving one of said machine parts, an operating circuit completed upon actuation of said relay to cause operation of said actuating means, at least one intermediate stage including a tube having a plate circuit and a grid circuit, a connection between the grid circuit of the second named tube and said source controlled by said relay to apply a bias to said second tube to hold the same non-conductive so long as the relay remains unactuated, a condenser connected in parallel with the last named connection in the region between the grid of the second named tube and the relay retaining a charge to hold said second tube non-conductive when said relay has operated, a lead connected with said last named connection having contact means closed by movement of said ma chine part to connect said lead with ground to provide a path to discharge the charge in said condenser andv thus make said second tube conductive, means for moving a second machine part, an operating circuit for the last named means, and a relay. connected with the plate circuit of said second tube and closing the last named circuit when said second tube becomes conductive.

2. An electronic control for a machine having a plurality of moving parts comprising an initiating stage including a tube having a plate circuit and a grid circuit, a relay connected in the plate circuit to be energized when the tube becomes conductive, a source of negative bias potential, a circuit between said source and the grid circuit to provide a bias to hold the tube nonconductive, manually operable means controlling said circuit to reduce said bias on the grid and thus render the tube conductive, actuating means for moving one of said machine parts, anoperating circuit completed upon actuation of said relay to cause operation of said actuating means, at least one intermediate stage including a tube having a plate circuit and a grid circuit, a connection between the grid circuit of the second named tube and said source controlled by said relay to apply a bias to said second tube to hold the same non-conductive so long as the relay remains unactuated, a condenser connected in parallel in the last named connection for retaining a bias charge to hold said second tube non-conductive when said relay has operated, a lead connected with said last named connection having ground contact means arranged to be closed by movement of said machine part to provide a path through said lead to ground for the discharge of said condenser to make said second tube conductive, means for moving a second machine part, an operating circuit for the last named means, a relay connected with the plate circuit of said second tube and closing the last named circuit when said second tube becomes conductive, and resetting means operated upon movement of a third moving part for restoring said relays to their initial positions.

3. An electronic control for a machine having a plurality of moving parts comprising a source of negative potential, an initiating stage including a tube having a plate circuit and a grid circuit, means for providing a negative cut off bias in the grid circuit to hold the tube non-conductive including an initiating circuit connected with the grid circuit and said source, a discharge condenser, and manually operable means for connecting said condenser with the initiating circuit to bleed sufiicient bias potential from the grid to render the tube conductive, a relay connected in the plate circuit to be made operative when the tube becomes conductive, an operating circuit completed by actuation of said relay to cause movement of one of said parts, a second stage comprising a second tube having a plate and a control grid, a control circuit extending from said source to the grid of the second tube to hold the second tube non-conductive, normally closed contact means in the control circuit at said relay to be opened upon operation of the relay, a timing condenser connected in parallel in said control circuit in the region between said contact means and said second tube retaining a bias charge suficient to hold said second tube nonconductive when said contact means is opened, a lead connected with the control circuit constituting a path to bleed said charge from the timing condenser, normally open contact means in said lead closed by movement of said part to allow the charge in the second mentioned condenser to bleed oii through said lead to render the second tube conductive, means connected with the plate circuit of the second tube to be energized when the second tube is made conductive, and an operating circuit completed by actuation of the last named means.

4. An electronic control for a machine having a plurality of moving parts comprising a source of negative potential, an initiating stage including a tube having a plate circuit and a grid circuit, means for providing a negative cut off bias in the grid circuit to hold the tube non-conductive including an initiating circuit connected with the'grid circuit and saidsource, a discharge condenser, and manually operable means for connecting said condenser with the initiating circuit to bleed suflicient bias potential from the grid to renderthe tube conductive, a relay connected in the plate circuit to be made operative when the tube becomes conductive, an operating circuit completed by actuation of said relay to cause movement of one of said parts, asecond stage comprising a second tube having a plate and a control grid, a control circuit extending from said source to the grid of the second tube to hold the second tube non-conductive, normally closed contact means in the control circuit at said relay to be opened upon operation of the relay, a timing condenser connected in parallel insaid control circuit in the region between said contact means and said second tube retaining a bias charge suiilcient to hold said second tube non-conductive when said contact means is opened, a lead connected with the control circuit constituting a path to bleed said charge from the timing condenser, normally open contact means in said lead closed by movement of said .part to allow the charge in the second mentioned condenser to bleed off through said lead to render the second tube'conductive, second relay means connected with the plate of the second tube to be energized when the second tube is made conductive, an operating circuit completed by said second rlay means upon energization of the same to cause movement of a second machine part, a third stage comprising a third tube having a plate and a grid,- a second control circuit extending from said source to the grid of the third tube to apply a bias to the latter to normally hold the third tube non-conductive, normally closed second contact means in said second 'control circuit at said second relay means to be opened when said second relay means is energized, a second timing condenser connected in parallel in said second control circuit in the region between the third tube and said second contact means for retaining a bias charge sufficient to hold said third tube non-conductive when said second contact means is opened, a second lead connected with said second control circuit, third contact means in said second lead closed by movement of said second machine part to provide a path through said second lead through which the charge in said second timing condenser bleeds off to render said third tube conductive, and relay means connected with the plate ofthe third tube to be energized to cause movement of a third machine part when the third tube is made conductive.

5. An electronic control for a machine having a plurality of moving parts comprising a source of negative potential, an initiating stage including a tube having a plate circuit and a grid circuit, means for providing a negative out 01f bias in the grid circuit to hold the tube non-conductive in cluding an initiating circuit connected with the grid circuit and said source, a discharge condenser, and manually operable means for connecting said condenser with the initiating circuit to bleed sufiicient bias potential from the grid to render the tube conductive, a relay connected in the plate circuit to be made operative when the tube becomes conductive, an operating circuit completed by actuation of said relay to cause movement of one of said parts, a second stage comprisinga second tube having a plate and a control grid, a control circuit extending from said source to the grid of the second tube to hold the second tube non-conductive,-normally closed contact means in the control circuitat said relay to be opened upon operation of the relay, a timing condenser connected in parallel in'zsaid control circuit in the region between said contact means and said second tube retaining a bias charge suflicient to hold said second tube non-conductive when said contact means is opened, a grounded adjustable potentiometer, a contact at said relay connected with the potentiometer and engaged by said contact means when said relay is operated to electrically conmeet the potentiometer with said control circuit to provide a resistance path for conducting away the charge in said timing condenser and thus delay firing of said second tube, a relay means in the plate circuit of saidtube energized when said second tube is fired, and an operating circuit completed by actuation of the last named relay.

6. An electronic control for a machine having a plurality of moving parts comprising a source of negative potential, an initiating stage including a tube having a plate circuit anda' grid circuit, means for providing a negative cutoff bias in the grid circuit to hold the tube nonconductive including an initiating circuit connected with the grid circuit and said source, a discharge condenser, and manually operable means for connecting saidcondenser withv the initiating circuit to bleed sufiicientbias potential from the grid to render the tube conductive, a relay connected in the plate circuit to be made operative when the tube becomes conductive, an operating circuit completed by actuation of said relay to cause movement of one of said parts, a second stage comprising a second tube having a plate and a control grid, a control circuitextending from said source to the grid of the second tube to hold the second tube non-conductive, normally closed contact means in thecontrol circuit at said relay to be opened upon opera-. tion of the relay, a timing-out condenser and a resistor connected in parallel in said control circuit in the region between said contact means and said second tube, the condenser being operable to retain a bias charge to hold said second tube non-conductive when said contact means is opened, a lead connected with the control circuit in a region to be in electrical connection with the timing condenser after opening of said contact means, normally open contact means in'sa-i'dlead closed by movement of said part to ground the lead and thus provide a dischargepath'for the charge in said timing condenser whereby the second tube is made conductive by'm'ovement or said part, a relay in the plate circuit of said operating circuit for causing operation of a first movable part, a relay controlling said operating circuit, a tube having a plate and a control grid, a connection between the plate and said relay for energizing the relay, a control circuit from said source to the grid applying a negative bias to the grid to hold the tube non-conductive, manually conditioned means for bleeding suffi cient negative bias potential from the gridto make the tube conductive and thus energize the relay to cause actuation of said first part, a second stage including a second actuating circuit for causing actuation of a second-movable-part;

a second relay for controlling said second circuit, a second tube having a plate and a control grid, a connection between the plate of the second tube and said second relay, a second control circuit from said source to the grid of the second tube applying a negative bias to the grid to hold the second tube non-conductive, the first mentioned relay including contactor means in said second control circuit normally completing the same and opening said second control circuit when the first mentioned relay is energized, a condenser connected in parallel with the second control circuit for holding a bias charge sufficient to hold the second tube non-conductive after actuation of the first mentioned relay, a ground bleed line connected with said second mentioned control circuit including a normally open contact closed by movement of said first part to bleed said charge from the timing condenser to make the second tube conductive, and a manually conditioned timing out mean for 22 timing out the second tube when movement of said first part is not to be employed as the timing factor, said timing out means including a grounding lead, an adjustable potentiometer in said lead, a contact on said lead engaged by said contactor means when said first mentioned relay is operated so as to connect said lead in said second control circuit, and a normally open manually closable switch in said lead, the charge in said condenser bleeding to ground through said lead when said switch is closed.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,207,055 Goodling July 9, 1940 2,422,020 Kingsmill June 10, 1947 OTHER REFERENCES Electronics, July 1950, pages 70-73. 

